Guinness Chocolate Cupcake
1 (12-ounce) bottle Guinness Extra Stout
1 cup (125 grams) all-purpose flour (spoon & leveled)
½ cup (41 grams) unsweetened natural cocoa powder
1½ teaspoons espresso powder
¾ teaspoon baking soda
¼ teaspoon salt
½ cup + 1 tablespoon vegetable or canola oil
1 cup (200 grams) packed light or dark brown sugar
2 large eggs, at room temperature
¾ cup full-fat sour cream, at room temperature
2 teaspoons pure vanilla extract
Mocha Guinness Buttercream:
2 tablespoons reduced Guinness
2 teaspoons espresso powder
1¼ cups (290 grams) unsalted butter, softened to room temperature
3½-4½ cups confectioners’ sugar
1 tablespoon (5grams) unsweetened natural cocoa powder
1 teaspoon pure vanilla extract
pinch of salt, to taste
In a small saucepan, bring the Guinness to a boil over medium-high heat. Once boiling, reduce to medium heat and allow to simmer until reduced down to 2/3 cup, about 20 minutes. Set ½ cup aside to cool for 10-15 minutes before using in the cupcake batter. While it’s warm, mix the rest of the reduced Guinness (about 2-2½ tablespoons) with the 2 teaspoons of espresso powder used in the frosting. Set this mixture aside for later.
Preheat the oven to 350°F. Line a 12-cup muffin pan with cupcake liners. Line a second pan with 4 liners-this recipe makes about 16 cupcakes. Set aside.
Whisk the flour, cocoa powder, espresso powder, baking soda, and salt together in a large bowl until thoroughly combined. Set aside. In a medium bowl, whisk the oil, brown sugar, eggs, sour cream, and vanilla together until completely smooth. Pour the wet ingredients into the dry ingredients, add the ½ cup reduced Guinness, then whisk until just combined. Do not over-mix. The batter will be on the thinner side.
Pour or spoon the batter into the liners. Fill each 2/3 full to avoid spilling over the sides or sinking. Bake for 19-22 minutes, or until a toothpick inserted in the center comes out clean. Don’t over-bake, which will dry out the cupcakes. Allow the cupcakes to cool completely before frosting.
Make the frosting: In a large bowl using a handheld or stand mixer fitted with a whisk attachment, beat the butter on high speed until completely smooth and creamy, about 2-3 minutes. Add the confectioners’ sugar starting with 3½ cups, cocoa powder, reduced Guinness/espresso powder mixture, and vanilla extract. Beat on low for 30 seconds then increase to high speed and beat until combined and creamy. Taste. Add the remaining sugar and a pinch of salt if desired.